1. Technical Field
The present invention relates to an imaging device for imaging a medium, and a medium transporting apparatus and a printing apparatus which includes the imaging device.
2. Related Art
As a printing apparatus which performs printing on a medium such as a sheet, a printing apparatus that is provided with an imaging device for imaging a lower surface of the medium transported by a transporting unit and a control device for calculating a transportation amount of the medium based on paper-surface properties of the lower surface of the medium imaged by the imaging device, and in which the control device controls the transporting unit based on the transportation amount of the medium is known (for example, refer to JP-A-2013-119439).
As this printing apparatus, for example, JP-A-2013-119439 discloses a printing apparatus which performs a template matching process for detecting a position where the similarity is maximized by moving a rectangular template set in advance in the image of the medium which is captured previously onto the image of the medium which is captured this time so as to calculate the transportation amount of the medium. That is, JP-A-2013-119439 discloses the printing apparatus which calculates the distance, in the transporting direction, between a position of the template in the image captured previously and a matched position of the template in the image captured this time as the transportation amount of the medium.
In addition, the printing apparatus disclosed in JP-A-2013-119439, as illustrated in FIG. 3 disclosed in JP-A-2013-119439, an imaging unit (an imaging device) is provided in a support base which supports the medium, and a control device is provided outside the support base and at a position separated from the support base.
Incidentally, the printing apparatus disclosed in JP-A-2013-119439 is required to include an electrical transmission line such as a cable for electrically connecting the imaging device and the control device. The electrical transmission line is wired outside the support base and the control device, and thus noise such as electromagnetic waves generated from other devices in the printing apparatus is likely to enter therein. For this reason, when the image having the paper-surface properties of the medium which is captured by the imaging device is transmitted to the control device through the electrical transmission line, the noise may enter the image in some cases. In this case, in the printing apparatus disclosed in JP-A-2013-119439, there is a concern in that when the printing apparatus performs the template matching process, a position of the template which is different from the position of the template to be matched in the image captured this time is erroneously set to the position where the similarity is maximized, and then the transportation amount of the medium is calculated based on the erroneous position of the template. For this reason, calculation accuracy of the transportation amount of the medium may be degraded. Such a problem is not limited to the printing apparatus, and may also occur in a medium transporting apparatus for transporting the medium.